Niang, 18, was a surprise selection in Massimiliano Allegri's side and the Frenchman missed a chance to give his side a strong advantage in the tie when he hit the post with Milan only 1-0 down.

A mistake from Javier Mascherano gave Niang a clear sight on goal and while he beat Victor Valdes, he was unable to give Milan an important away goal.

"We can't put all the blame on Niang. If he had scored, it would've been a different game, but this is football and you only get one chance," Flamini said. "Barcelona had a great performance, showed all their quality and are among the best teams in the world.

"We tried to play, but it was so difficult for us today. Perhaps we were a little nervous at the start, as we gave the ball away many times and didn't play the way we usually do.

"Barcelona pressed high up the field and it was tough for us to emerge. They played very quick passing too and deserve to be complimented. There is bound to be a psychological blow-back after a game like this, which is difficult to forget. Now we have to put it behind us and stay concentrated on Serie A."

Niang admitted he proved wasteful at the Camp Nou but denies he was overawed by the occasion of Champions League football.

"I did not feel afraid. I played the same way I do in Serie A, but I lost sharpness because you have to run so hard against Barcelona," Niang said. "I thought about it once, but five minutes later I had forgotten it. I hoped we would score after the break, but they are a great team and after the third goal it was all much more difficult.

"The 2-0 from the first leg was not enough to say we were through. Barcelona still would've had to get it wrong and when they are on a night like this, they're tough for everyone. Now we have to stay focused and think about the next game against Palermo."